DESCRIPTION (adapted from the abstract)This proposal is to study the molecular properties and location of the "aquaporin" and "connexin" channels in the lens. Lens aquaporin channels (AQP1 and MIP) mediate and regulate water permeability, a critical component of the hypothesized lens internal circulatory system. Lens connexin channels (Cx43, Cx46 and Cx50) are hypothesized to conduct and direct this circulation to be inward at the anterior and posterior poles and outward at the equator. This proposal aims to locate these channels in different regions of the lens, to quantify their density and to determine how changes due to aging and some naturally occurring mutations can lead to cataract formation. To identify the proteins, this proposal will use freeze fracture label electron microscopy. To study their functional properties, expression in Xenopus laevis oocytes will be used to allow measurements of molecular properties, electrolyte and nonelectrolyte fluxes and water permeability.